1. Field of the Invention
The present invention relates to umbrellas and more particularly to a tri-folded umbrella with improved characteristics such as enhanced frame, easy assembly, and more compactness.
2. Description of Related Art
Umbrella frame designs take many different forms. A conventional tri-folded umbrella is shown in FIG. 8. Such umbrella frame 70 has a number of disadvantages as observed by the present inventor. For example, a rivet is used in each of seven pivot joints 71 to 77. However, it is known that riveting is a tedious task. Also, uniform quality of riveting on the pivot joints 71 to 77 for each frame element is not easy to control. Typically, there are about total 42 to 56 pivot joints in an umbrella frame. Unfortunately, one defective pivot joint will soon make the whole umbrella unusable after a short period of time due to rust in the pivot joints. Further, stress tends to concentrate on the pivot joints. As a result, the frame is susceptible of break in folding or expanding the umbrella.
An FRP umbrella for solving the problem of rust in the pivot joint caused by riveting is proposed. However, the FRP umbrella still suffered from several disadvantages. For example, ribs of the FRP umbrella frame are shaped as cylindrical bar for providing a sufficient support to the frame. Also, a variety of plastic molded connecting elements and pivot elements are fitted at two ends and in intermediate section of the cylindrical rib, respectively. As such, each frame element is increased in size, resulting in a bulky FRP frame. This can cause difficulties in storage, packing, and delivery of the umbrella. Hence, a commercialized tri-folded FRP umbrella is still not available after such technique has been developed for more than 20 years. Thus, continuing improvements in the tri-folded FRP umbrella frame are constantly being sought.
It is an object of the present invention to provide a tri-folded umbrella having the advantage of smooth folding operation.
It is another object of the present invention to provide a tri-folded umbrella having the advantages of being lightweight, easy to pack, and delivery.
It is a further object of the present invention to provide an enhanced strength, durable tri-folded umbrella.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.